A case of Marfan syndrome with massive haemoptysis from collaterals of the lateral thoracic artery.

<bold>Background: </bold>Marfan Syndrome (MFS) is a heritable connective tissue disorder with a high degree of clinical variability including respiratory diseases; a rare case of MFS with massive intrathoracic bleeding has been reported recently.<bold>Case Presentation: </bold>A 32-year-old man who had been diagnosed with MFS underwent a Bentall operation with artificial valve replacement for aortic dissection and regurgitation of an aortic valve in 2012. Warfarin was started postoperatively, and the dosage was gradually increased until 2017, when the patient was transported to our hospital due to sudden massive haemoptysis. Computed tomography (CT) with a maximum intensity projection (MIP) revealed several giant pulmonary cysts with fluid levels in the apex of the right lung with an abnormal vessel from the right subclavian artery. Transcatheter arterial embolization was performed with angiography and haemostasis was achieved, which suggested that the bleeding vessel was the lateral thoracic artery (LTA) branch. CT taken before the incident indicated thickening of the cystic wall adjacent to the thorax; therefore, it was postulated that the bleeding originated from fragile anastomoses between the LTA and pulmonary or bronchial arteries. It appears that the vessels exhibited inflammation that began postoperatively, which extended to the cysts.<bold>Conclusion: </bold>We experienced a case of MFS with massive haemoptysis from the right LTA. We have to be aware of the possibility that massive haemoptysis could be induced in MFS with inflamed pulmonary cysts. [ABSTRACT FROM AUTHOR]